// edtFTPnet
// 
// Copyright (C) 2007 Enterprise Distributed Technologies Ltd
// 
// www.enterprisedt.com
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
// 
// Bug fixes, suggestions and comments should posted on 
// http://www.enterprisedt.com/forums/index.php
// 
// Change Log:
// 
// $Log: CustomFileParsers.cs,v $
// Revision 1.2  2008-07-15 05:42:57  bruceb
// refactor parsing code
//
// Revision 1.1  2007-11-12 05:19:19  bruceb
// unusual Unix parser
//
//
//

using System;
using System.Globalization;
using System.Text;
using EnterpriseDT.Util;
using EnterpriseDT.Util.Debug;

namespace EnterpriseDT.Net.Ftp
{
    /// <summary>  
    /// Custom file parser for an unusual Unix FTP server that returns LIST listings 
    /// in the form of -r-------- GMETECHNOLOGY 1 TSI         8 Nov 06 11:00:25 ,GMETECHNOLOGY,file02.csv,U,20071106A00001105190.txt
    /// </summary>
    /// <author>       
    /// Bruce Blackshaw
    /// </author>
    /// <version>      
    /// $Revision: 1.2 $
    /// </version>
    public class UnixFileParser2 : FTPFileParser
    {
        /// <summary> Symbolic link symbol</summary>
        private const string SYMLINK_ARROW = "->";

        /// <summary> Indicates symbolic link</summary>
        private const char SYMLINK_CHAR = 'l';

        /// <summary> Indicates ordinary file</summary>
        private const char ORDINARY_FILE_CHAR = '-';

        /// <summary> Indicates directory</summary>
        private const char DIRECTORY_CHAR = 'd';

        /// <summary>Date format 1</summary>
        private const string format1a = "MMM'-'d'-'yyyy";

        /// <summary>Date format 1</summary>
        private const string format1b = "MMM'-'dd'-'yyyy";

        /// <summary>Date format 2</summary>
        private const string format2a = "MMM'-'d'-'yyyy'-'HH':'mm:ss";

        /// <summary>Date format 2</summary>
        private const string format2b = "MMM'-'dd'-'yyyy'-'HH':'mm:ss";

        /// <summary>Date format 2</summary>
        private const string format2c = "MMM'-'d'-'yyyy'-'H':'mm:ss";

        /// <summary>Date format 2</summary>
        private const string format2d = "MMM'-'dd'-'yyyy'-'H':'mm:ss";

        /// <summary> Minimum number of expected fields</summary>
        private const int MIN_FIELD_COUNT = 8;

        /// <summary>array of format 1 formats</summary> 
        private readonly string[] format1 = {format1a, format1b};

        /// <summary>array of format 2 formats</summary>
        private readonly string[] format2 = {format2a, format2b, format2c, format2d};

        /// <summary> Logging object</summary>
        private readonly Logger log;

        /// <summary> Default constructor</summary>
        public UnixFileParser2()
        {
            log = Logger.GetLogger("UnixFileParser2");
        }

        /// <summary>
        /// Get flag indicating whether or not the most recent parse returned seconds.
        /// </summary>
        public override bool TimeIncludesSeconds
        {
            get { return true; }
        }

        /// <summary> 
        /// Parse server supplied string, e.g.:
        /// 
        /// -r-------- GMETECHNOLOGY 1 TSI         8 Nov 06 11:00:25 ,GMETECHNOLOGY,file02.csv,U,20071106A00001105190.txt
        /// 
        /// </summary>
        /// <param name="raw">  raw string to parse
        /// </param>
        public override FTPFile Parse(string raw)
        {
            // test it is a valid line, e.g. "total 342522" is invalid
            char ch = raw[0];
            if (ch != ORDINARY_FILE_CHAR && ch != DIRECTORY_CHAR && ch != SYMLINK_CHAR)
                return null;

            string[] fields = StringSplitter.Split(raw);

            if (fields.Length < MIN_FIELD_COUNT)
            {
                var listing = new StringBuilder("Unexpected number of fields in listing '");
                listing.Append(raw).Append("' - expected minimum ").Append(MIN_FIELD_COUNT).
                    Append(" fields but found ").Append(fields.Length).Append(" fields");
                throw new FormatException(listing.ToString());
            }

            // field pos
            int index = 0;

            // first field is perms
            string permissions = fields[index++];
            ch = permissions[0];
            bool isDir = false;
            bool isLink = false;
            if (ch == DIRECTORY_CHAR)
                isDir = true;
            else if (ch == SYMLINK_CHAR)
                isLink = true;

            string group = fields[index++];

            // some servers don't supply the link count
            int linkCount = 0;
            if (Char.IsDigit(fields[index][0])) // assume it is if a digit
            {
                string linkCountStr = fields[index++];
                try
                {
                    linkCount = Int32.Parse(linkCountStr);
                }
                catch (FormatException)
                {
                    log.Warn("Failed to parse link count: " + linkCountStr);
                }
            }

            string owner = fields[index++];


            // size
            long size = 0L;
            string sizeStr = fields[index++];
            try
            {
                size = Int64.Parse(sizeStr);
            }
            catch (FormatException)
            {
                log.Warn("Failed to parse size: " + sizeStr);
            }

            // next 3 fields are the date time

            // we expect the month first on Unix. 
            int dateTimePos = index;
            DateTime lastModified = DateTime.MinValue;
            var stamp = new StringBuilder(fields[index++]);
            stamp.Append('-').Append(fields[index++]).Append('-');

            string field = fields[index++];
            if (field.IndexOf(':') < 0)
            {
                stamp.Append(field); // year
                try
                {
                    lastModified = DateTime.ParseExact(stamp.ToString(), format1,
                                                       ParsingCulture.DateTimeFormat, DateTimeStyles.None);
                }
                catch (FormatException)
                {
                    log.Warn("Failed to parse date string '" + stamp + "'");
                }
            }
            else
            {
                // add the year ourselves as not present
                int year = ParsingCulture.Calendar.GetYear(DateTime.Now);
                stamp.Append(year).Append('-').Append(field);
                try
                {
                    lastModified = DateTime.ParseExact(stamp.ToString(), format2,
                                                       ParsingCulture.DateTimeFormat, DateTimeStyles.None);
                }
                catch (FormatException)
                {
                    log.Warn("Failed to parse date string '" + stamp + "'");
                }

                // can't be in the future - must be the previous year
                // add 2 days for time zones (thanks hgfischer)
                if (lastModified > DateTime.Now.AddDays(2))
                {
                    lastModified = lastModified.AddYears(-1);
                }
            }

            // name of file or dir. Extract symlink if possible
            string name = null;

            // we've got to find the starting point of the name. We
            // do this by finding the pos of all the date/time fields, then
            // the name - to ensure we don't get tricked up by a userid the
            // same as the filename,for example
            int pos = 0;
            bool ok = true;
            for (int i = dateTimePos; i < dateTimePos + 3; i++)
            {
                pos = raw.IndexOf(fields[i], pos);
                if (pos < 0)
                {
                    ok = false;
                    break;
                }
                else
                {
                    pos += fields[i].Length;
                }
            }
            if (ok)
            {
                name = raw.Substring(pos).Trim();
            }
            else
            {
                log.Warn("Failed to retrieve name: " + raw);
            }

            var file = new FTPFile(FTPFile.UNIX, raw, name, size, isDir, ref lastModified);
            file.Group = group;
            file.Owner = owner;
            file.Link = isLink;
            file.LinkCount = linkCount;
            file.Permissions = permissions;
            return file;
        }
    }
}